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Interior door lock cylinder. Why you should install a cylinder lock: principle of operation, advantages and disadvantages. If the front door lock is broken

There are many types of locks on the market of locking mechanisms: lever, crossbar, electronic. A common model is mortise door lock with a cylindrical mechanism, due to the high degree of safety, maintainability and affordable price.

What is a cylinder lock, types of structure

According to the GOST standard, a cylinder lock is: “a mechanism that moves and fixes the lock bolt in working positions and ensures the secrecy of the lock through the secrecy mechanism, i.e. a set of certain combinations of pins (plates, disks) corresponding to their own key.

These mechanisms take different forms:

  • Cylinder.
  • A circle.
  • A drop.
  • Triangle.

Cylinders with a European standard mechanism are presented on the door fittings market: they have a certain size and are made of a brass profile. Cases are made under them.

The cylinder mechanism is of two types:

  • pin.
  • Disk.

Pin cylinder lock device

A pin lock, a mortise cylinder (larva, snail) is a mechanism based on a core with a connector. It has code channels with code pins (their height determines the number of slots on the key) and a spring that pushes the code pins out of the channel. The code pins are in a profile, thanks to which they do not fly out. There are also support pins.

When the key enters the hole, each slot corresponds to a code pin, which is recessed to a certain depth (height). When unlocked, the code and support pins become exactly on the line between the body and the core, and it (the core) turns easily. In this case, the code elements remain in the core, the support elements with springs remain in the housing. That's the whole principle of work.

The shape of the cylinder (larva) adopted by the European standard is called: DIN-standard mechanism.

Pin cylinder lock details:

  • The case is the outer part of the castle, in which all the details are located.
  • The key is an independent unlocking part, with the help of which the secret is revealed when the leash is turned.
  • Cylinder or rotor - a replaceable part of a lock with a connector. It has pins.
  • Code pins or pins are details of the locking mechanism.
  • Locking pins or pins - together with the code pins block the rotor.
  • Return springs - with their help, the pins are blocked.
  • Leash - with its help the bolt moves.

Disc cylinder lock device

A door disk lock is a type of cylinder device, the mechanism of which is represented by a set of disks. Each disc has a uniquely shaped cutout. Corresponding slots are made on the key.

When unlocked, the discs of the mechanism move deeper towards the core. If the key fits, it turns easily. The secret of the lock places the discs at a certain angle, their recesses create a channel with balance - turn and the bolt moves.

The key is a sawn rod with slots, it is also called a semicircular key.

Padlocks cylinder with such a mechanism are less susceptible to freezing. A mortise disc lock is not recommended for outdoor installation. They are suitable for canvas with a large load. Suitable for entrance and interior doors made of metal, wood, plastic, glass.

Types of cylinder mechanism

There are several classifications according to different criteria.

By location on the canvas:

  • Consignment note - has one connector. On the other side is a handle.
  • Door mortise lock - its connector is through, that is, the key can be used from both sides. The cylinders of this lock are of two types: key + key, key + handle. The second type (with handles) is more convenient, but the first type is safer: if you insert a key into the slot from the inside, the lock cannot be opened from the outside.

In addition to these characteristics, there are cylinders of different lengths, the size depends on the thickness of the canvas. When buying, you must consider the size or you may encounter such problems:

  • Small cylinder - will be located deep in the body. This is ugly and inconvenient - the door will either be difficult to open, because the key will not reach the device mechanism.
  • Large cylinder - if it protrudes beyond the edges of the connector, this will make it easier for attackers to break it. If armor plates are installed in the body, the cylinder will not fit into the slot.

Cylinders are classified according to their location on the body: central and extreme.

Cylinder latch locks

The dead lock with a latch is functional, convenient in use.

Cylinder locks with latch latches close under mechanical action. It is an auxiliary element of the locking mechanism. The latch is available with and without a tongue lock, with one or two handles. Such locks are often used in residential and industrial premises.

False handles are used for entrance and interior doors. It has no functional feature, it is rather an element of decor. The convenience is that when changing the interior, in order for the locking device to fit into the image, it is enough to choose the handle according to the style.

Handles for entrance doors are resistant to external influences, made of durable materials (when compared with interior doors).

By type of pressing the handle are:

  • Push (for entrance doors).
  • Swivel (for interior doors).

The push handle is also suitable for interior structures. The choice depends on the preferences of the buyer.

How to choose a cylinder lock

In addition to such a criterion as the size of the larva, when choosing, it is necessary to pay attention to such characteristics:

  • Protection - you need to ask the sales assistant how durable the material was used to make the lock. The difficulty of opening when bumping, drilling, selecting a key depends on this.
  • Quality - how precisely the mechanism is complex, whether there have been cases of breakdown, how repairable a mortise lock with a latch is.
  • Additional functionality: this is recoding, installation of a gear mechanism, "anti-panic" and others.

The safety of the premises depends on how conscientiously the manufacturer adheres to these characteristics. The more reliable the device, the higher, as a rule, its cost will be.

A cylinder mortise lock with a latch is convenient because, if necessary, it is not necessary to dismantle the entire device - it is enough to replace the larva. You can replace the lock cylinder yourself by following the proposed algorithm:

  • Open the door, at the end find a screw on the bar near the cylinder.
  • Unscrew the screw.
  • If the locks are with handles, the cylinder can be easily reached, if without, you need to insert the key into the slot, turn it counterclockwise until it stops and pull it towards you.
  • Then move the key and handle slightly in the opposite direction so that the lever goes down - then the cylinder will easily come out of the body.
  • The new cylinder will be placed into the mechanism by the handle, or by a key inserted into it. Monitor the position of the lever - it must be completely secret.
  • Try to close the mortise lock with a latch by moving the front and back so that it closes freely.
  • Install the screw.
  • Check work.

To replace the overhead lock cylinder, the case must be removed from the canvas. Then everything is the same as with the previous one - find the screw, get the old cylinder and replace it with a new mechanism.

How cylinder devices are hacked

Unfortunately, the mortise lock cylinder is at the same time its weakest part - attackers use many methods to break the mechanism. Here are some of them:

  • Hacking with a master key: pick up the key to the lock with modern mechanism almost unrealistic, but thieves use special lockpicks, plus technical devices, such as a bumping machine. True, this option may also be ineffective: the technology provides for a complex secret: grooves, grooves. Therefore, to open a mortise mechanism with a latch, it will take a lot of time, which attackers most often do not have.

  • Breaking out the cylinder: a suitable key is selected that will fit into the well. Then they hit it with a hammer - all the details (pins, pins) are knocked down and the canvas opens. But this method is suitable if the lock is old or made of fragile material. You can protect yourself from such hacking by buying a durable mechanism or choosing a lock with a non-standard connector.
  • Drilling - effective method hacking. You can resist only by choosing a device with a mechanism made of high-strength materials.
  • Knocking out: with the help of physical force, improvised materials, the mechanism is broken. The solution is to acquire strong structures.

The strength of the material is the main factor protecting the room from unwanted penetration. But you need to remember that the mortise lock should be easy to use and last a long time.

Types of keys for a cylinder lock

The mortise lock with a cylinder latch is the most common. Such a device is distinguished not only by the type of fastening (mortise, invoice), but also by the type of key. Some are easy to copy, but there are models that cannot be imprinted, have millions of combinations.

  • English is an unreliable option, because it is a very common type. Due to the simplicity of the device, it is possible to pick up the key, which makes it easier for attackers. Easily breakable. Such a lock can be installed at the entrance to a room that does not have material values.

More about the features of the cylinder lock watch the video:

  • The Finnish key is a high indicator of reliability. The mechanism uses slotted discs, which are code parts. Used in padlocks.
  • Profile key - has a high level of secrecy, resists picks, easy to use. Has pins (active and passive), a large number of combinations.
  • The key of increased secrecy - in the manufacture of some models, 3D technologies are used. Mechanisms are hard to hack and require tools and training.

For modern locks with handles, the last two types of keys are more often used due to the high degree of reliability.

The online store of door locks offers cylinders (larvae) for locks of imported and domestic manufacturers. Also in the assortment are half-cylinders, oval cylinders and turn signals for cylinders (turntables).

The secret part of the cylinder lock is the cylinder or cylinder of the door lock, a product of precision technology. The lock cylinder is fixed inside or outside the lock itself and can only be turned with the key inserted into the hole. The secret mechanism is usually located in a standard case, thanks to which the cylinders of different manufacturers can be interchanged, i.e. they are compatible with each other. Lock cylinders are very common nowadays due to their ease of use ( small size the key, a weak turning force during rotation, is also the main plus - if necessary, not the entire lock changes, but only the lock cylinder - its secret part. Reinforced cylinder mechanisms and larvae with protection against most known methods of criminal autopsy are very popular.

One of the types of lock secrecy mechanisms is a cylinder mechanism. The structural element of the lock, of which the cylinder is a part, can only be activated when the native (regular) key is inserted into the lock hole. This category includes pin, disk, frame, magnetic and some special secrecy mechanisms. All manufacturers produce cylinder mechanisms of the same shape, thanks to which the "larvae" of different manufacturers are interchangeable with each other. This fact determines the huge popularity of mechanisms of this type in the segment of household locks.

The main advantage of cylinder mechanisms is the ease of replacing or repairing the lock. If it becomes necessary to change the lock, it is enough to replace only the central secret mechanism - the cylinder. The principle of operation of this mechanism is to line up the pins (needles) inside the cylinder in a certain combination, the pins take on the configuration of the inserted key. Someone else's key in the process of opening the door will enter the wrong combination of pins, and the lock will not open. The secrecy of the lock directly depends on the number of pins, their manufacturing accuracy, as well as protection against unauthorized manipulations.

The protection class of cylinder mechanisms varies from the first to the sixth. It depends on the number of pins, security mechanisms, case material, and additional anti-vandal features. When installing the mechanism in the lock, it is possible to equip it with additional protection - an armor plate.

Our online store represents only the main the lineup cylinder mechanisms. If you want to buy a cylinder whose model is not available on our website, you can always contact us and order the model you need.

In our online store you can buy cylinders for locks and other locking mechanisms at affordable prices and at any time convenient for you.

Most interior door locks have a larval secret mechanism, which, when turned with a native key, shifts the bolt of the lock and unlocks the door. A breakdown or malfunction of the mechanism is often associated with a malfunction of the larva.

What is a larva and when should it be replaced

A larva is a mechanism that is responsible for the secrecy of the locking device and ensures the uniqueness of the native key. He is metal cylinder in the circle. The core is inserted into an appropriately shaped hole in the lock body and fastened with a long screw from the side of the end plate to the door leaf. The rotating cylinder by means of a cam moves the bolt of the lock. The free rotation of the mechanism in the core case is prevented by small spring-loaded cylinders. To unlock the cylinder, you must insert a native key that has a code cut. He raises the pins in such a sequence that they unlock the mechanism and allow the lock bolt to move and unlock the door.

In principle, all larval locks work in the same way, but they can differ in the type of elements that make up the secret. There are larvae in which the pins (cylinders) are replaced by washers with a cut. In these secrets, the locking pin releases the inner cylinder when the cuts on the washers, when the native key is inserted, line up in a smooth groove into which this pin falls and allows the cylinder to turn.

As a rule, the disassembly of the secret mechanism is performed by masters. Such work is carried out not for repair, but for the purpose of recoding. These mechanisms are not subject to repair. In case of failure, they are simply replaced.

There can be many reasons why the core needs to be replaced. Here are the most common:

  • Natural wear of metal parts. Over time, the secret begins to jam, and later the mechanism finally jams.
  • Mechanical breaking of the lock by knocking out the larva. In this case, the rotary cam breaks, the core body is destroyed.
  • Key loss. The possibility that the key fell into the hands of a person with bad intentions is never excluded. In this case, you can secure your home only by changing the secret.

Replacing the core is a simple and inexpensive event. To determine how easy it will be to replace the secret mechanism and what this will require, it is necessary to establish what type of lock cylinder belongs to.

Types of larvae

The technology of how to disassemble the lock cylinder depends on the standard of the mechanism. There are the following types:

  • Cylinder larvae DIN standard. Almost interchangeable. The DIM standard establishes the basic dimensions of the larva (core height - 34 mm, cam width - 10 mm) and many other parameters. Secret mechanisms of this type are the most common. If there is such a core on the lock, then replacing it will not cause any difficulties. They are characterized by the shape of the seat in the lock body and the presence of a rotary lever, which is located inside the body and divides the larva into two parts.

  • Disc or cylinder cylinders for locks made according to the old RIM standard. Unlike larvae, DIM do not pass through the lock body, but are screwed to its body with screws. The transmission of rotation to the crossbar is carried out due to the flat limit switch. AT different models the mounting holes for the screws are located in different, so it is extremely difficult to pick up the larva. Such locks are mounted on the door in an overhead way. The mechanism for connecting the lock to the body and bolt of the DIN lock is not unified, and often its breakdown leads to the replacement of the entire locking device.

  • Cruciform larvae are not practical to change and repair. Only cores from the same type of locks are interchangeable. Their burglary resistance is low, and if such a lock is installed on the doors of the apartment, then it must be replaced with a more reliable one.

Cylinder locks

Larvae for locks of the DIN standard can be in various designs:

  • Secret type "key-key". The basic model of the secret mechanism, which has keyholes on both sides. The lock can only be opened with a key. In such models, with the key inserted on one side, it will not work to open the lock with the key on the other side.

  • The larva for the lock of interior doors of the "key-revolver" type. In such locks, it is possible to open the door from the inside with the help of a turntable (turntable), while on the outside the lock has a regular turnkey well. Mechanisms of this type will be convenient for installation on the front door of the apartment. You can open the lock from the inside in any situation (in the dark or in an emergency) without a key.

Important! If the usual larva of the “key-key” system was initially installed on the front door, and opening the door from the inside with a key brings a lot of inconvenience, then it can be replaced with a “key-turntable” model. This will make using the lock more convenient.

  • Larva-half-cylinder. It is installed on the door, where the stay of people on the one hand is not provided (pantries, utility rooms).

Important! RIM cores are similar to DIN half cylinders.


  • Cores with gear transmission of rotation from the cylinder to the crossbar. Such mechanisms are distinguished by smooth running, but due to design features, replacement of a larva with a gear is more complicated than replacing a conventional core. To do this, you will have to remove the entire castle completely.

How to remove the larva yourself

If the secret mechanism does not have visible mechanical damage, and it has not been hacked, then before disassembling the lock, it is first necessary to exclude ordinary contamination or drying of the lubricant from the reasons for the malfunction of the mechanism. To do this, lubricate the secret. Engine oil does not need to be poured into the larva, it is enough to dip the key in the lubricant, insert it into the lock and try to turn it several times. For these purposes, you can use WD-40 liquid.

If these measures did not help, or it was decided to replace the core for other reasons, they proceed to unscrew the secret:

  • Larvae for DIN standard locks are removed by unscrewing the fixing screw, the head of which is located on the front of the lock from the end door leaf. In some types of locks, the end plate can be covered with an additional protective plate. In this case, it is necessary to unscrew this plate.

Important! The signal that the screw has released the secret will be the mobility of the larva if it is loosened.

  • After unscrewing the screw, it is necessary to turn the inner cylinder of the lock so that the rotary cam is hidden in its body. Otherwise, it will prevent the removal of the core. You can turn the cylinder using a turntable in a “turn-key” type cylinder, or with a key.
  • After that, the core can be pulled out of the lock body.

To remove the rim lock cylinder of the RIM standard, a complete dismantling and disassembly of the entire mechanism is performed. As a rule, such locks are fastened with self-tapping screws through the side plate to the end of the blade and through the overhead housing to front side canvases.

After the lock is removed, access to the fixing screws of the larva will appear.

Choosing a new larva

The selection of a new larva is based on measurements taken from the old core.

If the door skin will not change, then you can use the old core as a template when buying a new one. If the replacement of the larva is accompanied by work on re-lining the door leaf, then measurements of the length of the core are made after finishing work is completed. At the same time, the thickness of the canvas is measured along with the lining.

Important! When upholstering the fabric with leatherette with foam rubber, take into account the clamping of the front plate of the door handle or the lining on the larva, which will press down the upholstery material. It is necessary to calculate the length of the core so that it protrudes from the door at the same level as the lining.

With different thicknesses of the cladding on different sides of the door leaf, the displacement of the hole for fastening the larva under the screw from its center is taken into account. If for a door it is necessary to buy an asymmetric larva with a “key-wrapping” system, then you need to pay attention to which side (long or short) the wrapping should be on.


When buying a secret in a store, pay attention to the metal from which the cylinder is made. Reliable and durable will be a mechanism made of brass or steel. Sellers in the store can offer a larva from the new TsAM alloy. This material has proven itself well, so you should not be afraid for its quality.

Installing a new larva in place

Installing a new secret in the lock is done in reverse order. The rotary cam is hidden in the body of the larva. It is inserted into the hole in the lock body. By turning the cylinder with a key, they find the position when the rotary cam is inside the lock body and will turn freely. After that, a long screw is inserted into the hole on the front plate of the lock from the end of the door and they catch the mounting hole in the body of the larva. It may not work right away.

After the screw goes along the thread of the mounting hole, it is tightened without a strong clamp. At the end, face strips or door handles are installed.

Larva replacement video:

Unlike the other popular group of lever type locks, in which malfunctions of the secret mechanism entail the replacement of the entire lock, in systems with a division of the locking device into two separate nodes, it is possible to repair by replacing the core. In this case, the main locking mechanism is not affected.

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The lock is a part of the door that protects the room from outside intrusion. Door locks require constant monitoring and maintenance. However, even with timely care of the device, various malfunctions may occur, which can be fixed on your own. What to do if the door lock is broken? A detailed answer to this question can be found by reading this article.

If the front door lock is broken

  • level. The device works by placing metal plates, called levers, in a certain order;
  • code. Most often used for entrance doors, as well as office and utility rooms.

The first thing to do when the lock breaks is to find out what type of device is installed on front door.

Typical breakdowns and how to fix them

Let's take a closer look at what to do if the front door lock is broken. Among the most common breakdowns are:

    1. the tongue of the locking mechanism is not included in the reciprocal bar. Such a malfunction of the door lock can occur for several reasons:
      • distortion of the door leaf;
      • skewed door frame;
      • blocking the mechanism with a patch plate of the lock;
      • loosening and loosening of the locking device.
  • fix all fasteners with a screwdriver;
  • straighten the door and/or frame. Editing the door is due to the adjustment of the hinges. If the problem is in the door frame, then reinstalling the striker in the right place is required;
  • if the tongue is blocked by a patch plate, then the lock must be disassembled, the position of the locking device corrected and the plate replaced.

All of the above works are carried out without the involvement of specialists.

  1. the door is difficult to open. Repair of the front door lock with this malfunction consists in adjusting the door leaf and the lock;
  2. jamming the door lock. The key is poorly inserted and / or difficult to turn. This failure most often occurs due to clogging of the mechanism. To fix the problem, you need to:
    • carefully disassemble the mechanism;
    • clean all internal elements. Use a stiff, dry brush to clean small parts. Larger parts are wiped with a rag;
    • lubricate the device;
    • assemble the mechanism and carry out several opening cycles for a systematic distribution of lubricant.
  1. jamming of the locking device. This problem is the most serious. To fix it, you will need to replace the secret part of the lock.

Replacing the lever lock

Many lever locks can be reprogrammed by the user. The reprogramming process consists in changing one or more lever plates. If the locking mechanism has such a function, then it is necessary:

  • buy a new set of levers. New keys are included with the kit;
  • sort plates by identity;
  • for the convenience of further installation, mark each pair of levers;
  • install a deadbolt stand in the lock body;
  • install levers according to the scheme that is attached to the kit or by selection, based on the free play of the key;
  • assemble the lock and check its performance.

The process of replacing the lever lock plates is discussed in more detail in the video.

Replacing the cylinder lock cylinder

How to fix a cylinder type door lock if necessary? This will require:

  • new secret part of the locking mechanism. To choose the right lock cylinder, it is recommended to first disassemble the device and measure the parameters of the central part. The easiest way is to go to a specialized store with the cylinder removed, where the sellers will independently select the desired device;
  • crosshead screwdriver.

Do-it-yourself lock repair, which consists in replacing the cylinder, is carried out according to the following scheme:

  1. on the end side of the door, at the location of the lock bar, there is a bolt that fixes the secret part of the mechanism. In order to remove the mask from the lock, it is necessary to loosen this lock with a screwdriver;
  1. after loosening the fasteners, the cylinder should easily exit the housing;

If the cylinder cannot be removed from the body, then insert the key, turn it half a turn and pull it slightly towards you.

  1. measure and purchase a new cylinder and a set of keys, which is attached to the secret part;
  1. insert the cylinder into place and fix it with a fixing bolt;
  1. check the operation of the lock.

Repair of an overhead lock also depends on the type of device and is fully consistent with the above schemes.

Code lock repair

To repair the code lock, in various situations, you must be guided by the diagrams presented above. Reprogramming of a mechanical device is carried out according to the following scheme:

  1. the lock is removed from the door and disassembled. For it is enough to dismantle the panel of buttons;
  2. under each button there is a plate that activates the locking mechanism;
  3. plates, which are directed into the lock with an oblique part, are active;
  4. to change the code, you need to turn the active plates to the edges of the lock, and those that will take part in the code combination to the center of the device.
  1. collect the lock and install it on the front door.

Electronic locks can be recoded without removing the device using the lock control panel or a special key included in the kit.

Breakdowns of locks of interroom doors and ways of their elimination

Broken interior door lock? The first thing to do is to identify the cause of the breakdown. The most common problems include:

  1. falling of the tongue of the locking device. Such a breakdown is most often caused by a spring holding the tongue. To repair the interior lock, you need:
    • dismantle the lock;
    • change the spring
    • assemble the mechanism.

All work can be carried out without removing the lock from the door.

  1. repair of the lock handle due to loosening of the device is carried out using a screwdriver of the required diameter. Before fastening, it is recommended to clean and lubricate the locking mechanism;
  2. jamming of the fixing latch. How to fix the lock on the door in a similar situation? The causes of the malfunction may be:
    • displacement of the internal elements of the device. The problem is fixed by parsing the lock and editing the displaced elements. In some cases, they may need to be replaced;
    • deformation and / or natural wear of locking mechanisms, cracking. To fix the problem, replacement of unusable elements is required. To make a replacement, it is recommended to contact the store, where experienced employees will help you select the components.
  3. if a lock with a key is installed on the interior door, you should read above how to repair such a device.

In most cases, repairing locks does not take much time and does not require special knowledge and skills. In order for the locking device to serve for a long period of time and not break, it is necessary to constantly take care of it, cleaning the locking mechanism from dirt and dust and lubricating it.